The present invention relates to tire valves, and more particularly, relates to a novel tubeless tire valve assembly of simple construction which is adapted to mounted on the rim of a tire, and wherein the tire valve assembly is constructed of a non-metallic material.
In the tire industry, particularly the segment relating to tubeless tires, it is currently the practice to provide tire valves which are adapted to be mounted on the rim for a tire, wherein the tire valve assembly includes a rubber grommet which is fitted over an elongate metallic valve stem, the latter of which is usually constituted of brass or similar metallic material, and in which the rubber grommet is either bonded to the valve stem or provides for an interference fit to thereby provide for a permanent connection or fastening between the valve assembly components. The grommet has an external configuration which adapts it to be sealing mounted in an aperture formed in a tire rim. Commonly, the valve stem is provided with an internally threaded bore portion to allow for insertion and threaded engagement with a suitable standard valve core structure, which is also constituted of metal, as is well known in the tire valve technology.
During the production of these tire valves, some problems have been encountered in attempting to provide for the satisfactory bonding of rubber grommets to metallic or brass valve stems in order to obtain a permanent fastening between these valve assembly components. Quite frequently, these problems are caused by the varying compositions of the brass components and of the rubber grommets, resulting in somewhat unpredictable physical characteristics which may adversely affect the degree of adhesion or bonding between the brass and rubber components. Consequently, at times it is possible that the pressure present within an inflated tire may cause the valve stem to be separated from the grommet, thereby leading to sudden deflation of the tire and possible road accidents to a vehicle employing such tire valve assemblies.
More recently, in lieu of adhesively bonding rubber grommets to brass valve stems in the construction of tire valves, particularly those for tubeless tires, valve assemblies have been developed in the industry wherein a metallic valve stem, preferably constituted of brass, has a rubber grommet mounted thereon with an interference or pressfit to provide for a permanent attachment or fastening between these components, and in which the valve stem is adapted to receive and mount a standard type of valve core. Among such valves which provide for a press-fitted engagement between a rubber grommet and a valve stem which is constituted of brass is U.S. Pat. No. 4,064,923, assigned to the Eaton Corporation, wherein the rubber grommet is mounted about a somewhat tapered portion of the brass valve stem in press-fitted relationship and is compressed at its ends between two flanges which are integrally formed with the valve stem. Although this tire valve arrangement is of a relatively simple two-piece construction, exclusive of the tire valve core, a tubeless tire valve arrangement of that type is rather expensive to manufacture due to the employment of brass for the valve stem, and moreover, does not always ensure that the rubber grommet will provide an adequate interference-fitted gripping engagement with the exterior surfaces of the valve stem.
More recently, tire valve constructions have been developed in the technology wherein the commonly employed metal or brass valve stem has been supplanted by a plastic material, for instance, nylon or glass fiber-reinforced nylon, with a rubber grommet being adhesively bonded to the valve stem.
Among such tire valve arrangements which are basically of a non-metallic construction is that disclosed in Lamson U.S. Pat. No. 4,171,119 wherein a valve stem of molded plastic material is assembled within a rubber grommet, and with the latter being adhesively bonded to the valve stem. In this instance, however, the valve stem is constituted of a plurality of molded parts which must then be assembled to provide for added physical support for an internal valve core and spring assembly and, although avoiding the use of brass or metal components, is of a rather complex, multi-component construction rendering the valve expensive to manufacture.
Thacker U.S. Pat. No. 3,712,326 discloses an inflation valve for tubeless tires wherein a valve stem which is constituted of a reinforced plastic material, such as glass fiber-reinforced nylon, is embedded within a rubber grommet and bonded thereto. Moreover, in order to provide for reinforcement in anchoring the valve stem within the grommet, the valve stem has an additional separate flange component molded thereto, and includes further molded sleeves in order to provide for the support of a valve core. Although this construction eliminates the utilization of metallic components, the structure of this tire valve is rather complex in nature and requires a plurality of molded components, thereby rendering the tire valve cumbersome and uneconomical.